Method for labeling individual cells

ABSTRACT

A disposable diaper is provided with a pair of side flaps lying transversely outside the associated side edge of an absorbent core, and the side flaps is formed by a first side sheet connected to the associated side edge portion of a topsheet lying in the vicinity of the associated side edge of the core and extending longitudinally of the diaper and a second side sheet connected to the associated side edge portion of the topsheet and the associated side edge portion of a backsheet both lying in the vicinity of the associated side edge of the core wherein both the first and second side sheets have a water pressure resistance of 100˜1500 mm and a breathing resistance of 0.03˜0.8 Kpa·s/m.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a disposable diaper adapted to absorband contain body fluids discharged thereon.

[0002] As one example of disposable diapers, there has already beenproposed a disposable diaper comprising a liquid-pervious topsheet, aliquid-impervious backsheet and a liquid-absorbent core disposed betweenthese two sheets, and the diaper further includes a pair of side flapslying outside transversely opposite side edges of the core andlongitudinally of the diaper and a pair of leak-barrier cuffs lying inthe vicinity of the transversely opposite side edges of the core andnormally biased to rise on the inner surface of the diaper. Each of theside flaps is formed by the associated side edge portion of thebacksheet lying transversely outside the associated side edge of thecore and extending longitudinally of the diaper and the associated outerside edge portion of the cuff lying transversely outside its fixed sideedge portion. In the side flap, the side edge portion of the topsheetterminates immediately outside the associated side edge of the corewhile the associated side edge portions of the backsheet and the cuff,respectively, extend transversely outward beyond the associated sideedge portion of the topsheet. The disposable diaper of such type isdisclosed, for example, in Japanese Patent Application Disclosure Nos.1996-289902 and 1996-322876.

[0003] The side flaps and the leak-barrier cuffs surround a wearer'slegs and partially occupy a crotch region of the wearer being prone toexcretion leak and stuffiness. To avoid these problems, it is desired toimprove both the water resistance and the breathability of the sideflaps and the cuffs.

[0004] If a plastic film is used as a stock material for the backsheet,a relatively high water resistance can be obtained but it is impossibleto obtain a desired breathability. Even if the plastic film is processedto have fine pores, it is impossible to obtain a breathabilitysufficient to prevent the interior of the diaper from becoming stuffy.

[0005] In the case of the backsheet and the cuffs both formed by anonwoven fabric, an effort to improve the water resistance by increasingthe basis weight of the synthetic resin fiber forming the nonwovenfabric will result in increasing the fiber density in the nonwovenfabric and correspondingly deteriorate the breathability. On thecontrary, an effort to improve the breathability by reducing the basisweight of the fiber forming the nonwoven fabric will reduce the fiberdensity in the nonwoven fabric and correspondingly deteriorate the waterresistance.

SUMMARY OF THE INVENTION

[0006] It is an object of this invention to provide a disposable diaperprovided with a pair of side flaps and a pair of leak-proof cuffspresenting optimized water pressure resistance and breathing resistanceso that both a sufficiently high water resistance and a sufficientlyhigh breathability can be ensured in the side flaps and the cuffs.

[0007] According to this invention, there is provided a disposablediaper comprising a liquid-pervious topsheet, a liquid-imperviousbacksheet and a liquid-absorbent core disposed therebetween, and formedwith a pair of side flaps lying outside transversely opposite side edgesof the core and extending longitudinally of the diaper, wherein: each ofthe side flaps is formed by a breathable and liquid-resistant first sidesheet connected to the associated side edge portion of the topsheetlying in the vicinity of the associated side edge of the core andextending longitudinally of the diaper and at least one breathable andliquid-resistant second side sheet connected to the associated side edgeportions of the top- and backsheets both lying in the vicinity of saidassociated side edge of the core or at least to the associated side edgeportion of the backsheet and extending longitudinally of the diaperunder the first side sheet wherein both the first and second side sheetshave a water pressure resistance of 100˜1500 mm and a breathingresistance of 0.03˜0.8 Kpa˜s/m.

[0008] With the disposable diaper according to this invention, each ofthe side flaps is formed by the first and second side sheets presentinga water pressure resistance of 100˜1500 mm and a breathing resistance of0.03˜0.8 Kpa·s/m. Adjustment of these resistance values in such ranges,respectively, ensures the side flap to present a sufficiently high waterpressure resistance as well as a sufficiently high breathability. As aresult, leak of excretion otherwise occurring through the side flap canbe reliably avoided and moisture generated within the diaper can bereliably breathed out to the exterior and thereby to avoid undesirablestuffiness otherwise generated within the diaper.

[0009] With the diaper 1 implemented to have the pair of leak-proofcuffs, it is ensured that these cuffs prevent a sufficiently high waterpressure resistance as well as a sufficiently high breathability so faras the breathing resistance of the first side sheet is adjusted within arange of 0.03˜0.8 Kpa·s/m. In this way, the diaper can prevent excretiondischarged thereon from leaking through the cuffs and breathe outmoisture to the exterior through the cuffs to avoid undesirablestuffiness otherwise generated within the diaper. Furthermore,adjustment of the water pressure resistance of the first side sheet tobe higher than that of the second side sheet(s) effectively preventexudation of excretion otherwise occurring through the cuffs toward theside flaps and at the same time prevent exudation of excretion otherwiseoccurring through the fist side sheet toward the second sheet(s).

[0010] The side flap comprising the first side sheet and two or moresecond side sheets is more effective than the side flap comprising thefirst side sheet and a single side sheet to improve its water pressureresistance and the diaper including such side flap is suitableparticularly as the diaper exclusively used by adult discharging arelatively large amount of excretion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a perspective view showing one embodiment of a partiallycutaway disposable diaper according to this invention;

[0012]FIG. 2 is a sectional view taken along line A-A in FIG.

[0013]FIG. 3 is a view similar to FIG. 1 showing an alternativeembodiment of this invention; and

[0014]FIG. 4 is a sectional view taken along line B-B in FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Details of a disposable diaper according to this invention willbe more fully understood from the description given hereunder withreference to the accompanying drawings.

[0016]FIG. 1 is a perspective view showing one embodiment of a partiallycutaway disposable diaper according to this invention and FIG. 2 is asectional view taken along line A-A in FIG. 1. A diaper 1 basicallycomprises a liquid-pervious topsheet 2, a liquid-impervious backsheet 3and a liquid-absorbent core 4 disposed between the top- and backsheets2, 3 and bonded to the inner surface of at least one of these two sheets2, 3. Configurationally, the diaper 1 has a front waist region 20, arear waist region 22 and a crotch region 21 extending between thesefront and rear waist regions 20, 22 as viewed longitudinally of thediaper 1. The diaper 1 further includes a pair of side flaps 5 extendinglongitudinally of the diaper 1 outside transversely opposite side edges4 a of the core 4 and a pair of leak-barrier cuffs 6 a normally biasedto rise on the inner surface of the diaper 1.

[0017] Each of the side flaps 5 comprises a first side sheet 6 bonded toa side edge portion 2 a of the topsheet 2 defined in the vicinity of theside edge 4 a of the core 4 and extending longitudinally of the diaper1, on one hand, and a second side sheet 7 bonded to a side edge portion3 a of the backsheet 3 defined in the vicinity of the side edge 4 a ofthe core 4 and extending longitudinally of the diaper 1, on the otherhand. Of the side flap 5, the first side sheet 6 overlies the topsheet 2and the second sheet 7 underlies the first side sheet 6. Both the firstand second side sheets 6, 7 are made of a nonwoven fabric formed bythermoplastic synthetic resin fiber. In the crotch region 21, the sideflap 5 has its outer contour laterally curved inwardly of the diaper 1,describing a circular arc, so that the diaper 1 as a whole presents anhourglass-like contour. The side flap 5 is provided between the firstand second sheets 6, 7 with a leg-hole's elastically stretchable member8 secured under tension to the inner surface of at least one of thesefirst and second side sheets 6, 7.

[0018] The first side sheet 6 extends inwardly of the diaper 1 from theside edge portion 2 a of the topsheet 2 to form each of the leak-barriercuffs 6 a. The leak-proof cuff 6 a comprises a fixed side edge portion 6a 1 bonded to the upper surface of the topsheet 2 along its side edgeportion 2 a by means of adhesive and extending longitudinally of thediaper 1, a free side edge portion 6 a 2 lying inside the fixed sideedge portion 6 a 1 and extending longitudinally of the diaper 1 andlongitudinally opposite fixed end portions 6 a 3 bonded to the uppersurface of the topsheet 2 as they are collapsed inwardly of the diaper1. The free side edge portion 6 a 2 is provided with an elasticallystretchable member 9 extending longitudinally of the diaper 1 andsecured under tension thereto so that a portion of the free side edgeportion 6 a 2 may wrap the member 9.

[0019] The first and second side sheets 6, 7 respectively have a waterpressure resistance of 100˜1500 mm and a breathing resistance of0.03˜0.8 Kpa·s/m. It should be understood that the breathing resistanceis preferably in a range of 0.05·0.6 Kpa·s/m.

[0020] The water pressure resistance of the side sheets may be enhanced,for example, by increasing the basis weight of the synthetic resin fiberforming the nonwoven fabric and by reducing the fiber intersticestherein. The breathing resistance may be alleviated, for example, byreducing the basis weight of the nonwoven fabric forming fiber andenlarging the fiber interstices therein. Enhancement of the waterpressure resistance and alleviation of the breathing resistance thusconflict with each other. However, it is possible for both the sideflaps 5 and the cuffs 6 a of the diaper 1 according to this invention tohave sufficiently high water pressure resistance as well as sufficientlyhigh breathability without victimizing any one of the water pressureresistance and the breathability by adjusting the water pressureresistance and the breathing resistance of the first and second sidesheets 6, 7 in the ranges as have been described.

[0021] The water pressure resistance of the side sheets 6, 7 less than100 mm would sometimes result in exudation and leakage of excretionthrough these side sheets 6, 7. The water pressure resistance of theside sheets 6, 7 exceeding 1500 mm, on the other hand, would inevitablyincrease the basis weight of the fiber forming these side sheets 6, 7and therefore the fiber density of the nonwoven fabric. The side sheets6, 7 would have their rigidity correspondingly increased, so the sideflaps 5 and the cuffs 6 a would give a diaper wearer uncomfortablefeeling as these side flaps 5 and cuffs 6 a come in contact with thewearer's crotch.

[0022] The breathing resistance of the side sheets 6, 7 less than 0.03Kpa·s/m would reduce the basis weight of the fiber forming the sidesheets 6, 7 to a level at which the side sheets 6, 7 have their waterpressure resistance unacceptably reduced and are impaired and brokendown. On the other hand, the breathing resistance of the side sheets 6,7 exceeding 0.8 Kpa·s/m would increase the basis weight of the fiberforming the side sheets 6, 7 and correspondingly deteriorate thebreathability thereof. As a result, it would be impossible for suchdiaper 1 to breathe moisture out from the interior of the diaper 1through the side flaps 5 and the cuffs 6 a and to prevent a stuffinessgenerated inside the diaper 1.

[0023] The side flap 5 has its water pressure resistance and breathingresistance substantially twice as high as those of the first and secondside sheets 6, 7 since the side flap 5 is formed by these first andsecond sheets 6, 7 placed upon each other. Concerning the rigidity, thisis not true, since it is not apprehended that the rigidity of one of thefirst and second side sheets 6, 7 might enhance the rigidity of theother although the side flap 5 comprises these first and second sidesheets 6, 7 are placed upon each other.

[0024] In the side flap 5, side edge portions 2 a, 3 a of the top- andbacksheets 2, 3, respectively, terminate immediately outside theassociated side edge 4 a of the core 4, and the first and second sidesheets 6, 7 extend outward beyond the associated side edge portions 2 a,3 a of the top- and backsheets 2, 3, as will be apparent from FIG. 2.The second side sheet 7 is partially disposed between the associatedside edge portions 2 a, 3 a of the top- and backsheets 2, 3,respectively, and bonded to the associated side edge portions 2 a, 3 aof the top- and backsheets 2, 3. The first and second side sheets 6, 7are placed upon each other and, in such relative position, have theirinner surfaces intermittently bonded to each other by means of adhesive.The cuffs 6 a cooperate with the topsheet 2 to form a pair of pockets Popening inward transversely of the diaper 1. An alternative arrangementis also possible such that the second side sheets 7 underlie thebacksheet 3 and are partially bonded to the respective side edgeportions 3 a of the backsheet 3.

[0025] The front and rear waist regions 20, 22 of the diaper 1 arerespectively provided along longitudinal ends thereof with waist-hole'selastically stretchable film-like members 10 transversely extendingbetween the top- and backsheets 2, 3 and secured under tension to theinner surface of at least one of these top- and backsheets 2, 3. In therear waist region 22, a pair of tape fasteners 11 extending inwardtransversely of the diaper 1 have their proximal end portions attachedto the side flaps 5, respectively. In the front waist region 20, arectangular strip of target tape 12 is attached to the surface of thebacksheet 3 so that the tape fasteners 11 may be anchored on this stripof target tape 12.

[0026] Referring to FIG. 1, the leg-hole's elastic members 8, thewaist-hole's elastic members 10 and the elastic members 9 bonded to thecuffs 6 a along their free side edge portions 6 a 2 are relieved oftension to form gathers along the respective longitudinal ends of thefront and rear waist regions 20, 22 as well as along the respective freeside edge portions 6a2 of the cuffs 6 a. As shown, the diaper 1 iscurved with its inner surface inside and contraction of the elasticmembers secured to the respective free side edge portions 6 a 2 of thecuffs 6 a causes the respective free side edge portions 6 a 2 of thecuffs 6 a to rise on the inner surface of the diaper 1.

[0027] The diaper 1 is formed with the pair of leg-holes and thewaist-hole (not shown) as the respective free side edge portions of thetape fasteners 11 are anchored on the strip of the target tape 12 bymeans of pressure-sensitive adhesive (not shown) applied on the innersurfaces of the free side edge portions.

[0028]FIG. 3 is a view similar to FIG. 1 showing an alternativeembodiment of this invention and FIG. 4 is a sectional view taken alongline B-B in FIG. 3. This alternative embodiment of the diaper 1 issimilar to that shown by FIG. 1 in that the diaper 1 comprises thetopsheet 2, the backsheet 3, the core 4 disposed between the top- andbacksheets 2, 3, the side flaps 5 lying outside the transverselyopposite side edges 4 a of the core 4 and extending longitudinally ofthe diaper 1 and the leak-barrier cuffs 6 a normally biased to rise onthe inner surface of the diaper 1, configurationally defining the frontwaist region 20, the rear waist region 22 and the crotch region 21extending between the front and rear waist regions 20, 22.

[0029] In the case of the diaper 1 shown by FIG. 3, the side flap 5comprises the side sheet 6 bonded to the associated side edge portion 2a of the topsheet 2 and extending longitudinally of the diaper 1 and twosecond side sheets 7 a, 7 b bonded to the associated side edge portion 2a of the topsheet 2 and to the associated side edge portion 3 a of thebacksheet 3, respectively, both extending longitudinally of the diaper1.

[0030] The second side sheets 7 a, 7 b are placed upon each other and,in such relative position, have their inner surfaces intermittentlybonded to each other by means of adhesive. The first side sheet 6 andthe second side sheets 7 a, 7 b respectively have a water pressureresistance of 100˜1500 mm and a breathing resistance of 0.03˜0.8Kpa·s/m. It should be understood that the breathing resistance ispreferably in a range of 0.05˜0.6 Kpa·s/m.

[0031] According to this alternative embodiment of the diaper 1, theside flap 5 has its water pressure resistance and breathing resistancesubstantially treble as high as those of the first and second sidesheets 6, 7 a, 7 b since the side flap 5 is formed by these first andsecond sheets 6, 7 a, 7 b placed one upon another. Compared to theprevious embodiment of the diaper 1 in which the side flap 5 comprisesthe first side sheet 6 and the single second side sheet 7, the side flap5 in this alternative embodiment presents an improved water pressureresistance somewhat victimizing its breathability. Accordingly, thediaper 1 adopting this alternative embodiment of the side flaps 5 issuitable as the diaper exclusively used for adult discharging arelatively large amount of excretion. In this embodiment also, it is notapprehended that the rigidity of one of the second side sheets 7 a, 7 bmight enhance the rigidity of the other and consequently the rigidity ofthe side flap 5 as a whole might become treble as high as those of therespective sheets 6, 7 a, 7 b although these second side sheets 7 a, 7 bare placed upon each other.

[0032] As will be apparent from FIG. 4, the side edge portions 2 a, 3 aof the top- and backsheets 2, 3, respectively, terminate immediatelyoutside the associated side edge 4 a of the core 4, and the first andsecond side sheets 6, 7 a, 7 b extend outward beyond the associated sideedge portions 2 a, 3 a of the top- and backsheets 2, 3. The second sidesheets 7 a, 7 b are disposed between the associated side edge portions 2a, 3 a of the top- and backsheets 2, 3, respectively, and the secondsheet 7 a is bonded to the topsheet 2 by means of adhesive while thesecond sheet 7 b is bonded to the backsheet 3 by means of adhesive. Thefirst and second side sheets 6, 7 a, 7 b are placed one upon anotherand, in such relative position, have their inner surfaces intermittentlybonded one to another by means of adhesive.

[0033] This invention may be implemented also in a manner that thediaper 1 has no leak-barrier cuffs 6 a. In this case, the first sidesheet 6 no more extends inward beyond the associated side edge portion 2a of the topsheet 2 transversely of the diaper 1 but may terminate atthe associated side edge portion 2 a of the topsheet 2 and the portionof the first side sheet 6 overlying or underlying the associated sideedge portion 2 a of the topsheet 2 is bonded to the upper or lowersurface of the topsheet 2. It is also possible to form the side flap 5by three or more second side sheets placed upon the first side sheet 6.

[0034] The water pressure resistance presented by the first side sheet 6and the second side sheets 7, 7 a, 7 b is preferably adjusted to be in arelationship of the first side sheet >the second sheets. of excretion,feces contains a relatively large amount of organic substances such asprotein and lipid and therefore presents a relatively low surfacetension on the nonwoven fabric. If the fiber forming this nonwovenfabric is polyolefine resin, an affinity between the organic substancesin feces and the polyolefine resin facilitates feces to permeate thenonwoven fabric. With the diaper 1 according to this invention, thewater pressure resistance of the first side sheet 6 may be adjusted tobe higher than those of the second side sheets 7, 7 a, 7 b as has beendescribed above not only to avoid undesirable exudation of feces fromthe cuff 6 a toward the side flap 5 but also to avoid undesirableexudation of feces from the first side sheet 6 toward the second sidesheets 7, 7 a, 7 b.

[0035] The inventors measured the breathing resistance presented by thefirst side sheet 6 and the second sheets 7, 7 a, 7 b using Model KES-F8of KATO TECH Co., Ltd. Measurement of the breathing resistance wasconducted five times for each sample and average values of these fivemeasurements were obtained as the breathing resistance of the first sidesheet 6 and the second side sheets 7, 7 a, 7 b.

[0036] The topsheet 2 may be formed by a liquid-pervious nonwoven fabricor porous plastic film, preferably by a liquid-pervious hydrophilicsheet. The backsheet 3 may be formed by plastic film or a laminatedsheet consisting of a hydrophobic nonwoven fabric and a plastic film.

[0037] The nonwoven fabric may be selected from a group including a spunlace nonwoven fabric, a needle punch nonwoven fabric, a melt blownnonwoven fabric, a thermal bond nonwoven fabric, a spun bond nonwovenfabric and a chemical bond nonwoven fabric. In addition, an SMS nonwovenfabric may be also useful, which comprises a melt blown nonwoven fabrichaving a high water resistance sandwiched between two layers of a spunbond nonwoven fabric each having high strength and softness. The SMSnonwoven fabric may be made by steps of sandwiching the melt blownnonwoven fabric between the two layers of spun bond nonwoven fabric andthen bonding these melt blown nonwoven fabric and spun bond nonwovenfabric using a press technique. As component fiber of the nonwovenfabric, there are available polyolefine, polyester and polyamide fibersand conjugated fiber of polyethylene/polypropylene or polyester and thelike.

[0038] The core 4 comprises a mixture of fluff pulp and highlyabsorptive polymer grains compressed to a desired thickness and entirelycovered with a water-pervious sheet (not shown) such as tissue paper.Bonding of the core 4, the elastic members 8, 9, 10 and the sheets 2, 3,6, 7, 7 a, 7 b may be carried out using suitable adhesive such as hotmelt adhesive or pressure-sensitive adhesive or a heat-sealingtechnique.

What is claimed is:
 1. A disposable diaper comprising a liquid-pervioustopsheet, a liquid-impervious backsheet and a liquid-absorbent coredisposed therebetween, and formed with a pair of side flaps lyingoutside transversely opposite side edges of said core and extendinglongitudinally of the diaper, wherein: each of said side flaps is formedby a breathable and liquid-resistant first side sheet connected to theassociated side edge portion of said topsheet lying in the vicinity ofthe associated side edge of said core and extending longitudinally ofthe diaper and at least one breathable and liquid-resistant second sidesheet connected to said associated side edge portions of said top- andbacksheets both lying in the vicinity of said associated side edge ofsaid core or at least to the associated side edge portion of saidbacksheet and extending longitudinally of the diaper under said firstside sheet wherein both said first and second side sheets have a waterpressure resistance of 100˜1500 mm and a breathing resistance of0.03˜0.8 Kpa·s/m.
 2. The disposable diaper according to claim 1 ,wherein said first side sheet forms a leak-barrier cuff overlying saidtopsheet and extending inward from the associated side edge portion ofsaid topsheet transversely of the diaper, said leak-barrier cuff beingnormally biased to rise on the inner surface of said diaper, saidleak-barrier cuff having a fixed side edge portion bonded to theassociated side edge portion of said topsheet, a free side edge portionlying transversely inside said fixed side edge portion and extendinglongitudinally of the diaper and longitudinally opposite end portionscollapsed transversely inward or outward and, in such collapsed state,bonded to longitudinally opposite ends of the diaper wherein said freeside edge portion is elastically stretchable longitudinally of thediaper.
 3. The disposable diaper according to claim 1 , wherein saidfirst and second side sheets are formed by a nonwoven fabric made ofthermoplastic synthetic resin fiber and said first side sheet has awater pressure resistance higher than that of said second side sheet.